1. Field of the Invention
The invention relates to a print unit cylinder for rotary presses. The print cylinder having a narrow non-printing gap parallel to the cylinder axis for accommodating a rubber blanket, pressplate, or printing plate ends, and also a filler piece for bridging the non-printing gap opening in such a way as to prevent cylinder vibration when two interacting cylinders roll over the non-printing gaps.
2. Background Information
A print unit cylinder featuring a filler piece arranged in its cylinder gap or in the pit and supported on the bottom of the cylinder gap is known from German Patent No. DE-A-35 40 581. The filler piece itself is composed of metal and is arranged in the central third of the cylinder. The outer contour of the filler piece is adapted with high accuracy to the bearer ring diameter or the reference diameter of the drive gears. A filler piece is also provided in a second cylinder, so that both filler pieces in the interacting cylinders roll over each other.
It has now become apparent that when, for example, two rubber blanket cylinders roll over each other, the metal filler pieces cause a disturbing noise when they come into contact with each other, especially at high machine speeds. Furthermore, due to the rigid design and seating of the filler pieces, a shock cannot be avoided when they come into contact with each other since the elastic rubber blankets have a different roll behavior. Consequently, the cylinders cannot be prevented from vibrating. Negative phenomena cannot be avoided, especially when print unit cylinders without bearer rings are used, even when extremely exact tolerances have been assigned to the filler pieces. In addition, wear of filler pieces cannot be avoided because of the considerable shock load borne across their specific short overall length.